1. Field
The following description relates generally to wireless communications, and more particularly to employing pilots communicated via secondary channels to enhance handing off in a wireless communication system.
2. Background
Wireless communication systems are widely deployed to provide various types of communication; for instance, voice and/or data can be provided via such wireless communication systems. A typical wireless communication system, or network, can provide multiple users access to one or more shared resources (e.g., bandwidth, transmit power, . . . ). For instance, a system can use a variety of multiple access techniques such as Frequency Division Multiplexing (FDM), Time Division Multiplexing (TDM), Code Division Multiplexing (CDM), Orthogonal Frequency Division Multiplexing (OFDM), and others.
Generally, wireless multiple-access communication systems can simultaneously support communication for multiple mobile devices. Each mobile device can communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations.
Wireless communication systems oftentimes employ one or more base stations that provide a coverage area. A typical base station can transmit multiple data streams for broadcast, multicast and/or unicast services, wherein a data stream may be a stream of data that can be of independent reception interest to a mobile device. A mobile device within the coverage area of such base station can be employed to receive one, more than one, or all the data streams carried by the composite stream. Likewise, a mobile device can transmit data to the base station or another mobile device.
Handoffs commonly occur within wireless communication systems. For instance, handoffs can occur between base stations and/or base station sectors. Handing off can be effectuated by a mobile device measuring a strength of a signal transmitted by one or more base stations and/or sectors. Wireless network deployments oftentimes use more than one frequency band for operation, while a mobile device typically has hardware capability to receive on only one frequency band at a time. Thus, the mobile device experiences diminished operating ability when in a geographic region where two (or more) signals are present, where at least one signal is from a first frequency band and at least another signal is from a second frequency band. In particular, the mobile device can be communicating on the first frequency band. Moreover, to measure the signal strength on the second frequency band (e.g., to enable handing off to a base station that operates upon the second frequency band), the mobile device commonly has to tune away from the first frequency band (e.g., since the mobile device can be unable to receive signals on more than one frequency band at a given time). Such tuning away can cause disruption in communication on the first frequency band, thereby diminishing quality of service. Further, conventional tuning away oftentimes necessitates utilizing a signaling protocol that can mitigate such disruption, which can be computationally expensive. Moreover, complex hardware design typically can be used to support fast switching between frequencies for these conventional techniques.